ricfly744
my understanding is that FMC speeds are ALWAYS for BALANCED rwy calculation
You are correct.
NEVER fly FMC speeds as they ONLY provide balanced field speeds.
The FMC does not take into account runway details such as but not limited to:
- Slope
- Stopway
- Clearway
- Obstacles (Most important!)
- Intersection details (unless entered as a shift)
This is
why EFB's and RTOW chars exist, to take these factors into account. Next time you use the RTOW/EFB see what the limit is for you calculation [calculation details in EFB]. Only on a runway where the above items are not any factor will balanced field speeds match FMC speeds.
Similarly, due to the same restriction in capability of FMC prediction of speeds, NEVER use DRY/WET/Skid-Resistant selection when calculating FMC speeds used or reference.
A very long wet runway may not at lower weights [using RTOW/EFB] require a reduced V1-wet, but the FMC will always provide a reduced V1 as it provides only Balanced Field data.